Nearly 7,000 different languages are spoken across the world. But how these languages evolved has long been a source of debate. Now, a group of German researchers has uncovered exactly how language evolves, solving one of the greatest linguistic mysteries.

For the study, newly published in the Proceedings of the National Academy of Sciences, researchers from the Max Planck Institute for the Science of Human History examined 81 Austronesian languages, searching for differences in their grammatical structures and lexicon. Because these languages were mainly from the same region, the team could model how they changed over time. And as it turns out, grammar changes faster than language—a finding that completely upends what we thought we knew about this evolution.

"The grammatical structures changed much more quickly and seemed to be more likely to be affected by neighboring languages, while the lexicon changed more as new languages were formed,” explained lead study author Simon Greenhill in a statement.

Mark Aronoff, a linguistics professor at Stony Brook University in NY, who specializes in language origin, says it's not that surprising to find that different parts of language evolve at different speeds. “I think that everyone believes that different aspects of language change different over time.”

But, he says, the idea that grammar changes faster than words was unforeseen. “Finding that grammar changes faster than words is counterintuitive,” said Aronoff. “I would have never thought that.”

What makes this discovery perhaps most intriguing is that it could challenge the notion of Universal Grammar (UG). This theory was made popular by the American linguist Noam Chomsky and suggests that grammar is innate. For example, children acquire the complexities of language so easily because they already have an instinctive knowledge of certain grammatical principles, according to the theory. But if grammar changes faster than vocabulary, then it may not be the best tool to study language changes—and therefore may not be as innate as UG suggests.

Lead study researcher Simon Greenhill told Newsweek that his research does not exactly challenge Chomsky's theory, he also agreed that it also doesn't fall neatly into the strict beliefs that derive from UG.

“The types of data we had in our analysis are really important features describing how languages are comprised and organized,” lead study author told Newsweek in an email. “But I suspect most proponents of UG would now say that they’re not things that followers of UG “care” about.”

Of course, the study has caveats and needs to be repeated before anything can be proven as fact. For example, while the research was conducted on a large number of languages, these languages are all very similar Pacific island languages, which may have affected the results.

“Every language has its own social situation and some of their findings may due to the fact that these are all Pacific languages and very small communities,” said Aronoff, who was not involved with the study.

The new work provides a groundbreaking insight into the potential evolution of language, but the results must now be replicated by other researchers. In the meantime, the rest of us, can look through the Urban Dictionary to remember how fast and creatively language evolves.